(1) Field of the Invention:
This invention relates to novel 5-substituted-3(2H)-pyridazinone derivatives, preparation thereof, and agricultural and horticultural fungicidal, insecticidal, acaricidal, nematicidal compositions containing said derivatives.
(2) Description of the Prior Art:
Hitherto, a pyridaphenthion (known under the trade name Ofunack) of the following formula IV has been put into practice as an active ingredient of an insecticide containing a 3(2H)-pyridazinone ring: ##STR3##
On the other hand, it is known that the compounds of the formula V and the compounds of the formula VI exhibit insecticidal and acaricidal action [refer to West Germany Pat. No. 2,732,101 as to the compounds (V); and Pesticide Sci. Vol 4, p. 775 (1973) and Vol. 7, p. 97 and 107 (1976), and Chem. Abstr. Vol. 90, 168636 u (1979), Vol. 92, 41867f (1980), Vol. 93, 132432x (1980) and Vol. 94, 84044u (1981) as to the compounds (VI)]: ##STR4## wherein, R.sup.3 and R.sup.4 are each a lower alkyl, Z is oxygen or sulfur atom, R.sup.5, R.sup.7 and R.sup.8 are each an alkyl, R.sup.6 is a halogen or an alkoxy, and A and B are each oxygen or sulfur.
All the compounds of the formulae IV, V and VI, however, are those classified as organic phosphorous insecticides and, therefore, apparently different from and not related at all to the compounds according to the present invention.
It is also known that the compounds of formula VII and those of the formula VIII are useful for Sheath blight (Pellicularia sasakii) (refer to, for example, Japanese Laid-Open Patent Publication No. 12879/78; and Japanese Laid-Open Patent Publications No. 111472/80 and 113767/81, respectively): ##STR5## wherein A denotes --CH.sub.2 CH.sub.2 -- or --CH.dbd.CH--, X.sup.1, X.sup.2 and X.sup.3 denotes, for example X.sup.1 .dbd.X.sup.3 .dbd.Cl, X.sup.2 .dbd.CH.sub.3 and X.sup.4 is hydrogen, halogen, alkyl, etc. X.sup.5 is chlorine, X.sup.6 is hydrogen or halogen.
Also the compounds (VII) and (VIII) are completely different from those of the present invention in that the former have a phenyl ring (which may be substituted) at 6-position but do not have a substituent at 2-position.
Thus present inventors have synthesized many kinds of 3(2H)-pyridazinone derivatives and searched on pesticidal activities thereof in order to develop novel and useful pesticides, and have found that such 3(2H)-pyridazinones that have specified substituents at 5-position exhibit excellent fungicidal, insecticidal, acaricidal, nematicidal activities to complete the invention.